EP2275186B1 - Filter material for air filters - Google Patents
Filter material for air filters Download PDFInfo
- Publication number
- EP2275186B1 EP2275186B1 EP09724703.5A EP09724703A EP2275186B1 EP 2275186 B1 EP2275186 B1 EP 2275186B1 EP 09724703 A EP09724703 A EP 09724703A EP 2275186 B1 EP2275186 B1 EP 2275186B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- fibers
- filter medium
- glass fibers
- short glass
- value
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000000463 material Substances 0.000 title description 5
- 239000003365 glass fiber Substances 0.000 claims description 104
- 239000000835 fiber Substances 0.000 claims description 97
- 239000011230 binding agent Substances 0.000 claims description 59
- 238000004062 sedimentation Methods 0.000 claims description 40
- 239000002994 raw material Substances 0.000 claims description 32
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims description 27
- 229910052796 boron Inorganic materials 0.000 claims description 27
- 239000002245 particle Substances 0.000 claims description 14
- 239000011521 glass Substances 0.000 claims description 9
- 239000000470 constituent Substances 0.000 claims description 5
- 101000582320 Homo sapiens Neurogenic differentiation factor 6 Proteins 0.000 claims description 2
- 102100030589 Neurogenic differentiation factor 6 Human genes 0.000 claims description 2
- 239000006185 dispersion Substances 0.000 description 42
- 238000000034 method Methods 0.000 description 28
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 27
- 230000000052 comparative effect Effects 0.000 description 25
- 235000013305 food Nutrition 0.000 description 25
- MQIUGAXCHLFZKX-UHFFFAOYSA-N Di-n-octyl phthalate Natural products CCCCCCCCOC(=O)C1=CC=CC=C1C(=O)OCCCCCCCC MQIUGAXCHLFZKX-UHFFFAOYSA-N 0.000 description 12
- BJQHLKABXJIVAM-UHFFFAOYSA-N bis(2-ethylhexyl) phthalate Chemical compound CCCCC(CC)COC(=O)C1=CC=CC=C1C(=O)OCC(CC)CCCC BJQHLKABXJIVAM-UHFFFAOYSA-N 0.000 description 12
- 239000007787 solid Substances 0.000 description 11
- 239000005871 repellent Substances 0.000 description 10
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 8
- 230000008569 process Effects 0.000 description 8
- 239000002002 slurry Substances 0.000 description 8
- 239000004094 surface-active agent Substances 0.000 description 8
- 230000002378 acidificating effect Effects 0.000 description 7
- 238000011156 evaluation Methods 0.000 description 6
- 239000003795 chemical substances by application Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 238000001914 filtration Methods 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 230000007935 neutral effect Effects 0.000 description 5
- 230000009467 reduction Effects 0.000 description 5
- 230000006378 damage Effects 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 230000035515 penetration Effects 0.000 description 4
- 229920005989 resin Polymers 0.000 description 4
- 239000011347 resin Substances 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 239000000654 additive Substances 0.000 description 3
- 239000005388 borosilicate glass Substances 0.000 description 3
- 230000003247 decreasing effect Effects 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 229920002050 silicone resin Polymers 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 238000004378 air conditioning Methods 0.000 description 2
- 239000002270 dispersing agent Substances 0.000 description 2
- -1 fatty acid esters Chemical class 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 238000011835 investigation Methods 0.000 description 2
- 239000004816 latex Substances 0.000 description 2
- 229920000126 latex Polymers 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000002940 repellent Effects 0.000 description 2
- 239000013049 sediment Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- VZGDMQKNWNREIO-UHFFFAOYSA-N tetrachloromethane Chemical compound ClC(Cl)(Cl)Cl VZGDMQKNWNREIO-UHFFFAOYSA-N 0.000 description 2
- 238000011179 visual inspection Methods 0.000 description 2
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 239000004925 Acrylic resin Substances 0.000 description 1
- KWIUHFFTVRNATP-UHFFFAOYSA-N Betaine Natural products C[N+](C)(C)CC([O-])=O KWIUHFFTVRNATP-UHFFFAOYSA-N 0.000 description 1
- 241000282320 Panthera leo Species 0.000 description 1
- 239000002202 Polyethylene glycol Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 101100219227 Vaccinia virus (strain Western Reserve) VACWR212 gene Proteins 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 125000003545 alkoxy group Chemical group 0.000 description 1
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 1
- 239000002280 amphoteric surfactant Substances 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 229960003237 betaine Drugs 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 235000014113 dietary fatty acids Nutrition 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000003292 diminished effect Effects 0.000 description 1
- 230000003467 diminishing effect Effects 0.000 description 1
- KPUWHANPEXNPJT-UHFFFAOYSA-N disiloxane Chemical class [SiH3]O[SiH3] KPUWHANPEXNPJT-UHFFFAOYSA-N 0.000 description 1
- 239000004815 dispersion polymer Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000000194 fatty acid Substances 0.000 description 1
- 229930195729 fatty acid Natural products 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000011491 glass wool Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 230000000116 mitigating effect Effects 0.000 description 1
- 239000002736 nonionic surfactant Substances 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 230000008520 organization Effects 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 229920001223 polyethylene glycol Polymers 0.000 description 1
- 229920005672 polyolefin resin Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 238000009877 rendering Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000009987 spinning Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000012209 synthetic fiber Substances 0.000 description 1
- 229920002994 synthetic fiber Polymers 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- 229920002803 thermoplastic polyurethane Polymers 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D39/00—Filtering material for liquid or gaseous fluids
- B01D39/14—Other self-supporting filtering material ; Other filtering material
- B01D39/20—Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
- B01D39/2003—Glass or glassy material
- B01D39/2017—Glass or glassy material the material being filamentary or fibrous
- B01D39/2024—Glass or glassy material the material being filamentary or fibrous otherwise bonded, e.g. by resins
-
- D—TEXTILES; PAPER
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
- D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
- D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
- D04H1/4209—Inorganic fibres
- D04H1/4218—Glass fibres
-
- D—TEXTILES; PAPER
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H13/00—Other non-woven fabrics
- D04H13/008—Glass fibre products; Complete installations for making them
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H13/00—Pulp or paper, comprising synthetic cellulose or non-cellulose fibres or web-forming material
- D21H13/36—Inorganic fibres or flakes
- D21H13/38—Inorganic fibres or flakes siliceous
- D21H13/40—Inorganic fibres or flakes siliceous vitreous, e.g. mineral wool, glass fibres
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
- D21H27/08—Filter paper
Definitions
- the present invention is an air filter medium, more specifically, a sub high efficiency or high efficiency air filter medium used for cleanrooms, cleanbenches, etc. in connection with the semiconductor, liquid crystal display, and biological/food industries or building air conditioning filters, air purifier application, etc. so as to filter particles in air.
- air filters can be classified roughly into the following categories: Coarse particle filters; ASHRAE filters; sub high efficiency filters; and high efficiency filters (HEPA filters, ULPA filters).
- HEPA filters, ULPA filters high efficiency filters
- sub high efficiency filters and high efficiency filters have a European standard, namely EN1822.
- EN1822 There are seven classes in EN1822 from U16 through H10 according to the collection efficiency level of the most penetrating particle size (MPPS).
- filter medium materials nonwoven glass fibers are often used for the production of air filter media.
- the glass fibers whose average fiber diameter is in the range of 100nm (sub- ⁇ m) ⁇ several tens of ⁇ m and whose most penetration particle size (MPPS) mentioned above is between 0.1 ⁇ m and 0.2 ⁇ m, are the main constituent of the filter medium.
- Patent Documents 1 and 2 a method in which the surface tension of the binder added to a filter medium is reduced by containing silicone resin so as to cancel or reduce the webbed membrane of the binder has been proposed.
- Patent Documents 1 and 2 a method in which the surface tension of the binder added to a filter medium is reduced by containing silicone resin so as to cancel or reduce the webbed membrane of the binder.
- the present inventors proposed an air filter medium in which a binder and a fluorochemical surfactant, whose minimum surface tension is 20 dyne/cm or less when the surfactant was added to pure water at 25°C, are attached on glass fibers that constituted the filter medium (Patent Document 3).
- This invention had some effect on solving the above problem. Nevertheless, the attachment of a fluorochemical surfactant enhanced wettability of the binder resin surface, sometimes diminishing the water repellency characteristic of the filter medium.
- Patent Document 4 propose a filter medium on which a polymer dispersion having an average particle size of 100nm or less and a fluorochemical surfactant having the minimum surface tension of 20mN/m or less when the surfactant is added to pure water at 25°C were attached. These proposals are limited to the binders to be attached on the filter media.
- JP 2007029916 A proposes that a filter medium contains glass fibers as main components and a condensate produced by hydrolyzing an alkoxysilane having at least three Alkoxy groups in a molecule and then condensing the hydrolysis products is used as a water-repelling agent mainly containing low molecular cyclic siloxane and emitting no organic out gas.
- a filter medium is provided containing glass fibers as main fibers, which scarcely emits organic out gas components at the time of use for ventilation and which has high water repellency and dust trapping capability and sufficient strength and is usable for every purpose such as air conditioning in buildings and semiconductor plants.
- the objective of the present invention is to provide an air filter medium having a lower pressure drop and a higher collection efficiency as compared to an air filter medium currently in use.
- an air filter medium comprising glass short fibers as its main fibers, characterized
- the main fibers are the fibers that constitute 70% or greater by mass of the total blended raw material fibers
- the glass short fibers are low boron short glass fibers having a fiber diameter of less than 5 ⁇ m and length to diameter ratio of approximately 500:1 to approximately 3,000:1, in which the constituent fibers of the air filter are dispersed uniformly and, when said constituent fibers at a diluted concentration of 0.04% by mass are allowed to stand for 12 hours, the sedimentation volume is 450cm 3 /g or greater. Furthermore, the sedimentation volume of the constituting fibers is used as the average fiber length index thereof.
- the air filter medium of the present invention can lower pressure drop and improve efficiency of the air filter medium of conventional technology. It can also improve the strength of the fllter medium after a binder is attached thereon.
- the filters used as the main fibers in the present invention are called short glass fibers.
- One type may be selected freely from short glass fibers having various diameters according to the requirements for filtering performance and other properties.
- Short glass fibers are glasswool fibers produced by flame attenuation, rotary spinning, etc., which constitute an essential component to maintain the filter medium's pressure drop at a given value and to obtain appropriate efficiency. Since the smaller the fiber diameter, the larger the efficiency, acquiring a high efficiency filter medium necessitates a blending of ultrafine glass fibers having a fine average diameter. Yet, the finer diameter of the fibers promote too mach pressure drop; therefore, an appropriate fiber diameter which balances the pressure drop must be selected. However, fibers having various fiber diameters may also be blended.
- fibers having a diameter of less than 5 ⁇ m are used.
- the glass of the glass fibers composition the majority composition for the air filter application is borosilicate glass, which also includes acid resistant C-glass and non-electrically conductive E-glass (non-alkaline glass), etc. Additionally, in order to prevent boron contamination during semiconductor processing, etc., low boron short glass fibers, silica short glass fibers, etc. may also be used.
- short glass fibers may be blended with 30% or less by mass of a secondary material (e.g., chopped glass fibers, natural fibers, organic synthetic fibers, etc.) having a fiber diameter of 5 ⁇ m or larger, which is larger than short glass fibers.
- a secondary material e.g., chopped glass fibers, natural fibers, organic synthetic fibers, etc.
- the main fibers of the present invention are the fibers that constitute 70% or greater by mass of the total blended raw material fibers.
- the present inventors vehemently investigated the correlation between the average fiber length of short glass fibers and the collection characteristics of air filter media and devised the present invention.
- the average fiber length of the short glass fibers is difficult to control due to the way they are produced, and their lengths are distributed in a wide range. What is more, it is generally believed the short glass fibers have a length to diameter ratio of approximately 500:1 ⁇ 3000:1. Until now, the fiber length has been determined under a microscope. But because the diameters of short glass fibers are finer than other fibers, an accurate and speedy determination has been extremely difficult. Nonetheless, it was found through our investigation that the use of the sedimentation volume method of the present invention allowed the average fiber length data of short glass fibers to be determined indirectly.
- the fibers released from water dispersant begins to sediment.
- the sedimentation volume of the present invention utilizes this phenomenon to quantify the sedimentation state of short glass fibers after dispersion under a given condition.
- the numeric value is used as an index of the average fiber length: The higher the numeric value, the longer the average length of short glass fibers is.
- the following concrete method was used to determine the sedimentation volume of the present invention:
- the raw material slurry in which glass fibers were dispersed at room-temperature (23°C) was collected in fractions, which was then diluted in room-temperature (23°C) pure water to 0.04% by mass.
- the diluted slurry was placed in a 250mL graduated cylinder having an inner diameter of 38 mm and allowed to stand for 12 hours.
- the sedimentation volume was calculated using the following mathematical formula 2.
- the present inventors investigated the relationship between the sedimentation volume and filtering property, namely the PF value, of the filter medium, and newly discovered that the larger the sedimentation volume, the higher the collection performance was. In other words, it was found that the longer the average length of short glass fibers, the higher the PF value was. Particularly, the PF value dramatically improves at a sedimentation volume of 450cm 3 /g or greater. The cause of this is not known in detail.
- the average length of fibers is short, the web of fibers constituting the filter medium is disturbed by the short glass fibers that are taken into voids thereof, resulting in a non-uniform filter medium with diminished filtering performance; in contrast, if the average length of fibers is long, the sedimentation volume becomes 450cm 3 /g or greater, which reduces the number of short glass fibers that disturb the web, resulting in a uniform filter medium with enhanced filtering performance.
- these fibers allow the average length of fibers to be substantially long, fibers constituting the filter medium are locked into each other well, improving the strength (e.g., tensile strength) of the filter medium after binder is added thereto, which is another effect.
- the relationship among the sedimentation volume, the filter medium PF value, and the filter medium strength holds not only for 100% by mass of short glass fibers, which are main fibers, but also similarly for 70% or greater by mass of main fibers.
- the sedimentation volume of the present invention can be achieved as follows: First, short glass fibers having a long average length is selected. Second, in the disintegration and dispersion processes during filter medium sheet making, short glass fibers should not be broken into pieces to shorten the average length. In view of the first, although there is no particular limit to the average length, it is important to select the best suited manufacturer because the method of manufacturing and conditions adopted by a short glass fiber manufacturer dictate different average fiber length characteristics. Alternatively, a manufacturer may find out the optimal condition through process condition control within the same organization. The second view is particularly important. In other words, even if the optimal short glass fibers are selected according to the first point of view, destruction of fibers no longer allows the original characteristics to be utilized.
- Fibers can be dispersed by the following methods, for example: (A) Mechanical dispersion by using a pulper, agitator, mixer, beater, or beater with blades (naginatabeater) while stirring fibers in water and (B) water vibration energy dispersion by using an ultrasonic oscillator, etc.
- A Mechanical dispersion by using a pulper, agitator, mixer, beater, or beater with blades (naginatabeater) while stirring fibers in water
- B water vibration energy dispersion by using an ultrasonic oscillator, etc.
- the latter is relatively advantageous in view of fiber destruction but requires more time for dispersion than the former; this means that each approach has its own advantages and disadvantages, and the methods cannot be limited to one.
- Destruction of fibers can be mitigated, for example, by a reduction of the dispersion energy through a reduction of the dispersion time or the number of rotations of an agitator, which, on the other hand, adversely affects dispersion performance of fibers, resulting in a filter medium sheet of a non-uniform web with a lower PF value.
- An optimal condition must be found for each dispersion method so that the constituting fibers are dispersed uniformly and sedimentation occurs at the sedimentation volume of the present invention or more.
- the state in which "the constituting fibers are dispersed uniformly” means the state in which after 50mL of the dispersed raw material slurry is collected and diluted 20 times in a 1 L graduated cylinder in water while shaking, a uniform fiber distribution free from sticking fibers or entangled fibers is observed by visual inspection.
- water to disperse the raw material fibers it is adjusted with sulfuric acid to be acidic in the pH range of 2 ⁇ 4 to improve dispersion.
- a pH neutral surfactant such as a dispersant may also be used.
- the desirable raw material solid concentration in the dispersion is 0.2 - 1.5% by mass. At below 0.2% by mass, the probability of the occurrence of fiber destruction increases; when over 1.5% by mass, fiber dispersion performance deteriorates. More desirable is 0.4 - 1.0% by mass.
- low boron short fibers In short glass fibers, particularly low boron short fibers must be handled with care during disintegration and dispersion processes. In other words, low boron short glass fibers, which contain little B 2 O 3 which reinforces fiber strength, are brittle and susceptible to breakage, necessitating careful handling. Therefore, process conditions must be controlled stringently.
- a no-binder filter medium which is entirely free from binder, having a PF value of at least 9.9 or greater for 0.1 ⁇ 0.15 ⁇ m particles can be produced.
- a filter medium having a PF value of at least 9.0 or greater can also be produced.
- filter media having the same as or more than the above-mentioned PF value could not be produced.
- Particularly low boron short glass fibers had a lower PF value than other short glass fibers, and the filter medium that performs better than this could not be made.
- the PF value is limited to that of a no-binder filter medium because the filter property PF value of the air filter medium made by using glass fibers (henceforth may be abbreviated to the "glass fiber filter medium” or simply the “filter medium”) is subjected to the effects greatly by organic binder chemicals and additives that are added to enhance the strength of the filter medium.
- organic binder chemicals and additives that are added to enhance the strength of the filter medium.
- the PF value may increase due to organic binder chemicals and additives, or in some cases, the PF value may reach the level of the no-binder filter medium or higher.
- the no-binder PF value can be investigated for the organic binder added-filter medium by using the following method:
- the organic binder component is removed by sintering the filter medium in a furnace at 450°C for two hours rendering the near-perfect no-binder state (Some additives vanish at 450°C).
- a solvent for example, hot water, an organic solvent such as toluene, acetone, methyl ethyl ketone, carbon tetrachloride, chloroform, etc.
- an ultra critical fluid such as ultra critical carbon dioxide, ultra critical water, etc.
- extraction of the organic binder component from the filter medium renders the no-binder state.
- the sedimentation volume of the present invention can also be determined by dispersing the no-binder filter medium in water in such a way that fibers are not destroyed.
- the organic binder of the present invention is not limited to a particular type.
- synthetic resins such as acrylic resin, urethane resin, epoxy resin, olefin resin, polyvinyl alcohol resin, etc.
- these binder resins in the form of aqueous solution or aqueous emulsion are added to a filter medium by impregnation through immersion, or coating.
- an acetylene-based or fluorochemical surfactant may also be added thereto.
- water-repellent agents may be added in order to make the filter medium.
- these water-repellent agents, as well as binder resins are added to the filter medium by immersion or spraying.
- the sheet is dried preferably at 110 - 150°C by using a hot air dryer or roll dryer.
- Acidic water of pH 2.5 with sulfuric acid was added to 90% by mass of borosilicate short glass fibers having an average fiber diameter of 0.65 ⁇ m (106-475 manufactured by Johns-Manville Corporation) and 10% by mass of borosilicate short glass fibers having an average fiber diameter of 2.70 ⁇ m (110X-475 manufactured by Johns-Manville Corporation) to give a concentration of 0.5% by mass.
- These raw materials were deflaked for a minute by using a food mixer (Product No.
- the deflaked dispersion was dispersed uniformly. Then, the deflaked raw materials were diluted to a concentration of 0.1% by mass in the same acidic water and made into a wet sheet of paper by using a handmade sheet molder, followed by drying at 130°C by using a roll dryer to obtain a filter medium having a basis weight of 70g/m 2 .
- Example 1 As to Example 1, except that the mixer voltage of Example 1 was converted to 60V (actual amperage of 2.9A), the raw materials were deflaked for a minute in the same manner as in Example 1. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m 2 was obtained in the same manner as in Example 1.
- Example 1 As to Example 1, except that the mixer voltage of Example 1 was converted to 50V (actual amperage of 2.8A), the raw materials were deflaked for a minute in the same manner as in Example 1. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m 2 was obtained in the same manner as in Example 1.
- Acidic water of pH 2.5 with sulfuric acid was added to 90% by mass of low boron short glass fibers having an average fiber diameter of 0.65 ⁇ m (A06F manufactured by Lauscha Fiber International) and 10% by mass of low boron short glass fibers having an average fiber diameter of 2.70 ⁇ m (A26F manufactured by Lauscha Fiber International) to give a concentration of 0.5% by mass.
- These raw materials were deflaked for a minute in a mixer while the voltage supplied to the mixer was converted from the rated 100V to 60V (actual amperage of 3.0A). The deflaked dispersion was dispersed uniformly.
- the deflaked raw materials were diluted to a concentration of 0.1% by mass in the same acidic water and made into a wet sheet of paper by using a handmade sheet molder, which was dried at 130°C by using a roll dryer to obtain a filter medium having a basis weight of 70g/m 2 .
- Example 4 As to Example 4, except that the mixer voltage was converted to 50V (actual amperage of 2.9A), the raw materials were deflaked for a minute in the same manner as in Example 4. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m 2 was obtained in the same manner as in Example 4.
- Example 1 As to Example 1, except that a standard disintegrator was adopted in place of the mixer, and the raw materials were deflaked by a standard disintegrator (JIS P 8220 enacted in 1998) at a rated voltage of 100V for a minute, the same process as Example 1 was used. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m 2 was obtained in the same manner as in Example 1.
- a standard disintegrator JIS P 8220 enacted in 1998) at a rated voltage of 100V for a minute
- Example 4 As to Example 4, except that a standard disintegrator was adopted in place of the mixer, and the raw materials were deflaked by a standard disintegrator at a rated voltage of 100V for 30 seconds, the same process as Example 4 was used. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m 2 was obtained in the same manner as in Example 1.
- Borosilicate short glass fibers made by a manufacturer which is different from that of Example 1 was used. Acidic water of pH 2.5 with sulfuric acid was added to 90% by mass of ultra fine glass fibers having an average fiber diameter of 0.65 ⁇ m (B06F manufactured by Lauscha Fiber International) and 10% by mass of ultra fine glass fibers having an average fiber diameter of 2.70 ⁇ m (B26R manufactured by Lauscha Fiber International) to give a concentration of 0.5% by mass. These raw materials were deflaked for a minute in a mixer while the mixer voltage was converted from the rated 100V to 80V (actual amperage of 2.9A). The deflaked dispersion was dispersed uniformly.
- the deflaked raw materials were diluted to a concentration of 0.1% by mass in the same acidic water and made into a wet sheet of paper by using a handmade sheet molder, which was dried at 130°C by using a roll dryer to obtain a filter medium having a basis weight of 70g/m 2 .
- Example 8 As to Example 8, except that the mixer voltage of 80 V was converted to 70V (actual amperage of 2.9A), the raw materials were deflaked for a minute in the same manner as in Example 8. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m 2 was obtained in the same manner as in Example 8.
- Example 4 acrylic latex (Trade Name: VONCOAT AN-155. Manufacturer: Dainippon Ink and Chemicals, Inc.) and a fluorochemical repellent agent (Trade Name: LIGHT-GUARD T-10. Manufacturer: Kyoeisha Chemical Co., Ltd.) were mixed to make a slurry of binder having a solid component ratio by mass of 100/5.
- the resulting wet sheet of paper was impregnated therein and dried at 130°C by using a roll dryer.
- a filter medium having a basis weight of 70g/m 2 and an attached binder amount (solid content) of 5.5% by mass was obtained.
- Example 1 As to Example 1, except that the rated voltage of 100V (actual amperage of 2.9A) was adopted for the mixer voltage, the raw materials were deflaked for a minute in the same manner as in Example 1. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m 2 was obtained in the same manner as in Example 1.
- Example 1 As to Example 1, except that the mixer voltage of Example 1 was converted to 80V (actual amperage of 2.9A), the raw materials were deflaked for a minute in the same manner as in Example 1. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m 2 was obtained in the same manner as in Example 1.
- Example 1 As to Example 1, except that the mixer voltage was converted to 40V (actual amperage of 2.6A), the raw materials were deflaked for a minute in the same manner as in Example 1. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m 2 was obtained in the same manner as in Example 1.
- Example 4 As to Example 4, except that the rated voltage of 100V (actual amperage of 3.0A) was adopted for the mixer voltage, the raw materials were deflaked for a minute in the same manner as in Example 4. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m 2 was obtained in the same manner as in Example 1.
- Example 4 As to Example 4, except that the mixer voltage was converted to 70V (actual amperage of 3.0 A), the raw materials were deflaked for a minute in the same manner as in Example 4. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m 2 was obtained in the same manner as in Example 4.
- Example 4 As to Example 4, except that the mixer voltage was converted to 40V (actual amperage of 2.6A), the raw materials were deflaked for a minute in the same manner as in Example 4. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m 2 was obtained in the same manner as in Example 4.
- Example 1 As to Example 1, except that a standard disintegrator was adopted in place of the mixer, and the raw materials were deflaked by using a standard disintegrator at a rated voltage of 100V for two minutes, the same process as Example 1 was used. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m 2 was obtained in the same manner as in Example 1.
- Example 4 As to Example 4, except that a standard disintegrator was adopted in place of the mixer, and the raw materials were deflaked by using a standard disintegrator at a rated voltage of 100V for a minute, the same process as Example 4 was used. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m 2 was obtained in the same manner as in Example 1.
- Acrylic latex (Trade Name: VONCOAT AN-155. Manufacturer: Dainippon Ink and Chemicals, Inc.) and a fluorochemical repellent agent (Trade Name: LIGHT-GUARD T-10. Manufacturer: Kyoeisha Chemical Co., Ltd.) were mixed to make a binder liquid having a solid component ratio by mass to be 100/5.
- the resulting liquid was sprayed onto the wet sheet obtained in Comparative Example 5, and then dried at 130°C by using a roll dryer.
- a filter medium having a basis weight of 70g/m 2 and an attached binder amount (solid content) of 5.5% by mass was obtained.
- the pressure drop was determined by the use of a micropressure gauge while blowing air to a filter medium having an effective area of 100cm 2 at an area wind speed of 5.3cm/sec.
- the upstream to downstream count ratio was determined by using a laser particle counter manufactured by Lion Corporation: Air containing poly-disperse DOP (dioctyl phthalate) particles generated by a Raskin nozzle was blown through a filter medium having an effective area of a 100cm 2 at an area wind speed of 5.3cm/sec.
- the target particles had a diameter in the range of 0.1 - 0.15 ⁇ m.
- the DOP efficiency (%) was obtained by using the equation: 100 - (DOP penetration).
- the PF value which is the filter performance index of a filter medium was obtained by using the following Mathematical Formula 1: The higher the PF value, the higher the efficiency or the lower the pressure drop is.
- Mathematical Formula 1 The higher the PF value, the higher the efficiency or the lower the pressure drop is.
- Mathematical Formula 1 The higher the PF value, the higher the efficiency or the lower the pressure drop is.
- PF - Value log 10 ⁇ 1 - efficiency % / 100 pressure drop Pa / 9.81 ⁇ x - 100 *The pressure drop in the mathematical formula 1 is determined when air passes the filter medium at a face velocity of 5.3cm/s (Unit: Pa).
- Test strips cut out to a size of 1 inch width x 130mm length from a binder-attached filter medium was collected. They were spun stretched by a length of 100mm at a stretching speed of 15 mm/min by using a constant speed strograph (Strograph M1 manufactured by Toyo Seiki Co., Ltd.).
- the dispersion performance of the constituting fibers was evaluated as follows: 50mL of the dispersed raw material slurry was collected and diluted 20 times in a 1 L graduated cylinder in water while shaking, which was subjected to visual inspection. The uniform dispersion condition free from sticking fibers or entangled fibers is considered to be an excellent dispersion performance. "O” represents excellent dispersion performance, and "X” represents poor dispersion performance.
- the binder component was removed from the binder-attached filter medium which was kept and sintered in an electric furnace at 500°C for 30 minutes.
- the pressure drop, DOP efficiency, PG value of the filter medium after binder was removed were determined by the previously described experiments (1), (2), and (3).
- the sedimentation volume of the filter medium after binder was removed was determined in such a way that some area of the removal treated-filter medium was placed in pure water at room temperature (23°C) for 3 hours to be dispersed in the ultrasonic vibration treatment to obtain a slurry having a concentration of 0.04% by mass . Measurements were taken for the slurry by the method described in Paragraph 0013.
- Table 1 shows the results for the filter medium produced under the condition in which the mixer voltage was reduced and the number of rotation of the mixer blades was decreased. Between the rated voltage 100V and 80V, the sedimentation volume is low and the PF value level is also low. This is an indication that fibers were broken and shortened due to the high rotation number mixer processing. Under the condition of 70V - 50V, the sedimentation volume reaches over 450cm 3 /g and the PF value over 9.9, which indicates that a reduction of rotation number reduced the occurrence of fiber breakage, thereby significantly improving filter properties. However, in the 40V condition, the number of rotation is too small, deteriorating fiber dispersion performance and decreasing the PF value, although the sedimentation volume is high.
- Table 2 shows an example of low boron short fibers.
- a reduction in the number of rotations of the mixer blades provides the sedimentation volume of 450cm 3 /g or greater, which improves the PF value to 9 or more.
- the fact that the deterioration of fiber properties causes the PF value to diminish in the 40V condition is also the same.
- low boron short glass fibers are much more brittle than borosilicate short glass fibers, narrowing the range of suitable number of rotations. Even after an improvement is made, the PF value level is lower than that of borosilicate short glass fibers due to the properties of fibers themselves.
- Table 3 shows an example in which a standard disintegrator is used in place of a food mixer.
- the standard disintegrator as compared to a mixer, provides different blade shapes and stirring conditions. Nonetheless, the PF value can be improved by using an appropriate disaggregation time to establish the sedimentation volume of 450cm 3 /g or greater. Furthermore, the excessively long disaggregation time indicates the advancement of fiber breakage.
- Table 4 shows the example in which the same borosilicate glass short fibers of a different manufacturer were used.
- the sedimentation volume reached 450cm 3 /g or greater and the PF value 9.9 or greater.
- the average fiber length of the short glass fibers used in Examples 8 and 9 is surmised to be longer than that of the fibers used in Example 1 and Comparative Example 2.
- Table 5 shows the example of a binder-attached filter medium which was deflaked under the same condition as Examples 4 and Comparative Example 5 in which low boron short glass fibers were used.
- the attached binder increases the pressure drop with decreasing the PF value, while maintaining the same rate of decrease.
- the filter properties of the no-binder filter medium which is the base, is reflected to the properties on the binder-attached filter medium. This is supported by the fact that, after the binder is removed, the property values of the no-binder filter medium, namely the sedimentation volume, pressure drop, efficiency, and PF value, are nearly reproduced.
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Filtering Materials (AREA)
Description
- The present invention is an air filter medium, more specifically, a sub high efficiency or high efficiency air filter medium used for cleanrooms, cleanbenches, etc. in connection with the semiconductor, liquid crystal display, and biological/food industries or building air conditioning filters, air purifier application, etc. so as to filter particles in air.
- Conventionally, the air filter particle collection technology is used to efficiently collect particles on a sub-µm or µm unit. Depending on the targeted particle size and particle collection efficiency, air filters can be classified roughly into the following categories: Coarse particle filters; ASHRAE filters; sub high efficiency filters; and high efficiency filters (HEPA filters, ULPA filters). Among these filters, sub high efficiency filters and high efficiency filters have a European standard, namely EN1822. There are seven classes in EN1822 from U16 through H10 according to the collection efficiency level of the most penetrating particle size (MPPS). There are also other high efficiency filter standards such as IEST-RP-CC001 (USA), JIS Z 4812 (Japan), etc., and the materials used for sub high efficiency filters and high efficiency filters are those that satisfy these air filter standards. As to filter medium materials, nonwoven glass fibers are often used for the production of air filter media. The glass fibers, whose average fiber diameter is in the range of 100nm (sub-µm) ∼ several tens of µm and whose most penetration particle size (MPPS) mentioned above is between 0.1 µm and 0.2 µm, are the main constituent of the filter medium.
- Key properties required for the air filter medium, besides collection efficiency, includes pressure drop, which is an indicator of a filter medium's air resistance. In order to increase the collection efficiency of the filter medium, the proportion of small diameter-glass fibers must be increased. However, this causes an increase in pressure drop of the filter medium at the same time. Since a large pressure drop increases the load on suction fan operation, the running costs of power are increased, which is a problem. In view of energy conservation, a reduction in pressure drop in filter media is required. Particularly in recent years, the trend in increasing volumetric airflow for air filters invited a growing demand for mitigating pressure drop and increasing collection efficiency to reduce running costs of fans used in cleanrooms, cleanbenches, etc.
- As a means to overcome the problem, a method in which the surface tension of the binder added to a filter medium is reduced by containing silicone resin so as to cancel or reduce the webbed membrane of the binder has been proposed (Patent Documents 1 and 2). However, in recent years, particularly in the field of semiconductors, it was found that the diffusion of a small amount of low molecular siloxane contained in silicone resin into air in a cleanroom caused adverse effects on the yield in the manufacturing of large scale integrated circuits (LSI); this makes the use of silicone resin difficult in itself.
- Previously, the present inventors proposed an air filter medium in which a binder and a fluorochemical surfactant, whose minimum surface tension is 20 dyne/cm or less when the surfactant was added to pure water at 25°C, are attached on glass fibers that constituted the filter medium (Patent Document 3). This invention had some effect on solving the above problem. Nevertheless, the attachment of a fluorochemical surfactant enhanced wettability of the binder resin surface, sometimes diminishing the water repellency characteristic of the filter medium. In order to improve this drawback, the present inventors proposed a filter medium on which a polymer dispersion having an average particle size of 100nm or less and a fluorochemical surfactant having the minimum surface tension of 20mN/m or less when the surfactant is added to pure water at 25°C were attached (Patent Document 4). These proposals are limited to the binders to be attached on the filter media.
- Moreover, for glass fiber base sheets proposed were a manufacturing method in which glass fibers were deflaked in neutral water, then neutral paper was made by using the water to which an N-alkyl betaine type amphoteric surfactant was added (Patent Document 5), and a manufacturing method in which glass fibers were deflaked in neutral water, then neutral paper was made by using the water to which a non-ionic surfactant of polyethylene glycol fatty acid esters was added (Patent Document 6). However, these methods resulted in low filtering medium strength due to a large amount of residual surfactant contained in the filter medium. Also proposed was another method for making glass fiber filter papers for ultra low penetration air filters comprising 5 - 15% by weight of glass fibers having a fiber diameter in the range of 0.05 - 0.2µm and 95 ∼ 85% by weight of glass fibers having another diameter (Patent Document 7). Yet, the glass fibers having a diameter in the range of 0.05 - 0.2µm were too costly and could not be adopted for commercially acceptable filter media, which was another problem.
- Nevertheless, these methods were proposed in view of binders, glass fiber sheet making, and glass fiber blending, while little investigation has been made into properties of glass fibers themselves, the main component of the filter medium.
- Patent Document 1:
JP 02041499A - Patent Document 2:
JP 02175997 A - Patent Document 3:
JP 10156116 A - Patent Document 4:
JP 2004160361 A - Patent Document 5:
JP 62021899 A - Patent Document 6:
JP 61266700 A - Patent Document 7:
JP 62004418 A -
JP 2007029916 A - The objective of the present invention is to provide an air filter medium having a lower pressure drop and a higher collection efficiency as compared to an air filter medium currently in use.
- This objective is achieved by providing an air filter medium comprising glass short fibers as its main fibers, characterized In that the main fibers are the fibers that constitute 70% or greater by mass of the total blended raw material fibers, the glass short fibers are low boron short glass fibers having a fiber diameter of less than 5 µm and length to diameter ratio of approximately 500:1 to approximately 3,000:1, in which the constituent fibers of the air filter are dispersed uniformly and, when said constituent fibers at a diluted concentration of 0.04% by mass are allowed to stand for 12 hours, the sedimentation volume is 450cm3/g or greater. Furthermore, the sedimentation volume of the constituting fibers is used as the average fiber length index thereof.
- The air filter medium of the present invention can lower pressure drop and improve efficiency of the air filter medium of conventional technology. It can also improve the strength of the fllter medium after a binder is attached thereon.
- The filters used as the main fibers in the present invention are called short glass fibers. One type may be selected freely from short glass fibers having various diameters according to the requirements for filtering performance and other properties. Short glass fibers are glasswool fibers produced by flame attenuation, rotary spinning, etc., which constitute an essential component to maintain the filter medium's pressure drop at a given value and to obtain appropriate efficiency. Since the smaller the fiber diameter, the larger the efficiency, acquiring a high efficiency filter medium necessitates a blending of ultrafine glass fibers having a fine average diameter. Yet, the finer diameter of the fibers promote too mach pressure drop; therefore, an appropriate fiber diameter which balances the pressure drop must be selected. However, fibers having various fiber diameters may also be blended. Usually, fibers having a diameter of less than 5µm are used. As to the glass of the glass fibers composition, the majority composition for the air filter application is borosilicate glass, which also includes acid resistant C-glass and non-electrically conductive E-glass (non-alkaline glass), etc. Additionally, in order to prevent boron contamination during semiconductor processing, etc., low boron short glass fibers, silica short glass fibers, etc. may also be used. Furthermore, as long as the objective of the present invention is achieved without any problem, short glass fibers may be blended with 30% or less by mass of a secondary material (e.g., chopped glass fibers, natural fibers, organic synthetic fibers, etc.) having a fiber diameter of 5µm or larger, which is larger than short glass fibers. However, the main fibers of the present invention are the fibers that constitute 70% or greater by mass of the total blended raw material fibers.
- The present inventors vehemently investigated the correlation between the average fiber length of short glass fibers and the collection characteristics of air filter media and devised the present invention. The average fiber length of the short glass fibers is difficult to control due to the way they are produced, and their lengths are distributed in a wide range. What is more, it is generally believed the short glass fibers have a length to diameter ratio of approximately 500:1 ∼ 3000:1. Until now, the fiber length has been determined under a microscope. But because the diameters of short glass fibers are finer than other fibers, an accurate and speedy determination has been extremely difficult. Nonetheless, it was found through our investigation that the use of the sedimentation volume method of the present invention allowed the average fiber length data of short glass fibers to be determined indirectly. In other words, as short glass fibers having a specific gravity of approximately 2.5 are dispersed in water and allowed to stand still, the fibers released from water dispersant begins to sediment. However, if the average length of glass fibers is long, fibers hold on to each other or interact with each other in some other way in water, making it difficult for them to sediment. The sedimentation volume of the present invention utilizes this phenomenon to quantify the sedimentation state of short glass fibers after dispersion under a given condition. The numeric value is used as an index of the average fiber length: The higher the numeric value, the longer the average length of short glass fibers is.
- The following concrete method was used to determine the sedimentation volume of the present invention: The raw material slurry in which glass fibers were dispersed at room-temperature (23°C) was collected in fractions, which was then diluted in room-temperature (23°C) pure water to 0.04% by mass. The diluted slurry was placed in a 250mL graduated cylinder having an inner diameter of 38 mm and allowed to stand for 12 hours. The sedimentation volume was calculated using the following mathematical formula 2.
[Math 1]
Now, the standing time was set to 12 hours because this is the condition in which raw material sedimentation is stabilized to a certain degree. Although, in the present invention, the diluted concentration does not vary the sedimentation volume greatly, but affects it to some degree; therefore, the sedimentation volume is limited to 0.04% by mass. A graduated cylinder with graduations is used as a measuring container in the present invention. However, any container that has a cylindrical shape (e.g. tall beakers, test tubes, etc.) may be used. - The present inventors investigated the relationship between the sedimentation volume and filtering property, namely the PF value, of the filter medium, and newly discovered that the larger the sedimentation volume, the higher the collection performance was. In other words, it was found that the longer the average length of short glass fibers, the higher the PF value was. Particularly, the PF value dramatically improves at a sedimentation volume of 450cm3/g or greater. The cause of this is not known in detail. However, the following mechanism is conceivable: If the average length of fibers is short, the web of fibers constituting the filter medium is disturbed by the short glass fibers that are taken into voids thereof, resulting in a non-uniform filter medium with diminished filtering performance; in contrast, if the average length of fibers is long, the sedimentation volume becomes 450cm3/g or greater, which reduces the number of short glass fibers that disturb the web, resulting in a uniform filter medium with enhanced filtering performance. What is more, these fibers allow the average length of fibers to be substantially long, fibers constituting the filter medium are locked into each other well, improving the strength (e.g., tensile strength) of the filter medium after binder is added thereto, which is another effect. The relationship among the sedimentation volume, the filter medium PF value, and the filter medium strength holds not only for 100% by mass of short glass fibers, which are main fibers, but also similarly for 70% or greater by mass of main fibers.
- The sedimentation volume of the present invention can be achieved as follows: First, short glass fibers having a long average length is selected. Second, in the disintegration and dispersion processes during filter medium sheet making, short glass fibers should not be broken into pieces to shorten the average length. In view of the first, although there is no particular limit to the average length, it is important to select the best suited manufacturer because the method of manufacturing and conditions adopted by a short glass fiber manufacturer dictate different average fiber length characteristics. Alternatively, a manufacturer may find out the optimal condition through process condition control within the same organization. The second view is particularly important. In other words, even if the optimal short glass fibers are selected according to the first point of view, destruction of fibers no longer allows the original characteristics to be utilized. Fibers can be dispersed by the following methods, for example: (A) Mechanical dispersion by using a pulper, agitator, mixer, beater, or beater with blades (naginatabeater) while stirring fibers in water and (B) water vibration energy dispersion by using an ultrasonic oscillator, etc. The latter is relatively advantageous in view of fiber destruction but requires more time for dispersion than the former; this means that each approach has its own advantages and disadvantages, and the methods cannot be limited to one. Destruction of fibers can be mitigated, for example, by a reduction of the dispersion energy through a reduction of the dispersion time or the number of rotations of an agitator, which, on the other hand, adversely affects dispersion performance of fibers, resulting in a filter medium sheet of a non-uniform web with a lower PF value. An optimal condition must be found for each dispersion method so that the constituting fibers are dispersed uniformly and sedimentation occurs at the sedimentation volume of the present invention or more. Here, the state in which "the constituting fibers are dispersed uniformly" means the state in which after 50mL of the dispersed raw material slurry is collected and diluted 20 times in a 1 L graduated cylinder in water while shaking, a uniform fiber distribution free from sticking fibers or entangled fibers is observed by visual inspection. For the condition of water to disperse the raw material fibers, it is adjusted with sulfuric acid to be acidic in the pH range of 2 ∼ 4 to improve dispersion. However, a pH neutral surfactant such as a dispersant may also be used. The desirable raw material solid concentration in the dispersion is 0.2 - 1.5% by mass. At below 0.2% by mass, the probability of the occurrence of fiber destruction increases; when over 1.5% by mass, fiber dispersion performance deteriorates. More desirable is 0.4 - 1.0% by mass.
- In short glass fibers, particularly low boron short fibers must be handled with care during disintegration and dispersion processes. In other words, low boron short glass fibers, which contain little B2O3 which reinforces fiber strength, are brittle and susceptible to breakage, necessitating careful handling. Therefore, process conditions must be controlled stringently.
- By using the short glass fiber raw material having the sedimentation volume of the present invention for short glass fibers excluding low boron short glass fibers, a no-binder filter medium, which is entirely free from binder, having a PF value of at least 9.9 or greater for 0.1 ∼ 0.15µm particles can be produced. Moreover, by using low boron short glass fibers, a filter medium having a PF value of at least 9.0 or greater can also be produced. In the past, when the technology that controls sedimentation volume was not available, filter media having the same as or more than the above-mentioned PF value could not be produced. Particularly low boron short glass fibers had a lower PF value than other short glass fibers, and the filter medium that performs better than this could not be made. It is believed that, as mentioned before, this is because the fibers were brittle and susceptible to breakage and the fiber length was short. However, the glass surface characteristics are different from those of borosilicate glass, which makes it difficult to improve the PF value thereof to the level of borosilicate short glass fibers even with some improvement.
- Here, the PF value is limited to that of a no-binder filter medium because the filter property PF value of the air filter medium made by using glass fibers (henceforth may be abbreviated to the "glass fiber filter medium" or simply the "filter medium") is subjected to the effects greatly by organic binder chemicals and additives that are added to enhance the strength of the filter medium. As the organic binder that bonds the intersection between filters forms a film in a web of fibers, more pressure is lost in the filter medium, lowering the PF value. In contrast, the PF value may increase due to organic binder chemicals and additives, or in some cases, the PF value may reach the level of the no-binder filter medium or higher. Nevertheless, since an improvement of the PF value for the no-binder filter medium is expected to raise the standard for the totality of PF value for the filter medium after an organic binder is added, there is a good deal of inevitability in paying attention to the PF value of the no-binder filter medium.
- Note that the no-binder PF value can be investigated for the organic binder added-filter medium by using the following method: The organic binder component is removed by sintering the filter medium in a furnace at 450°C for two hours rendering the near-perfect no-binder state (Some additives vanish at 450°C). Yet available is another method in which the organic binder component used in a filter medium is eluted by a solvent, for example, hot water, an organic solvent such as toluene, acetone, methyl ethyl ketone, carbon tetrachloride, chloroform, etc., or an ultra critical fluid such as ultra critical carbon dioxide, ultra critical water, etc. In this method, extraction of the organic binder component from the filter medium renders the no-binder state. The sedimentation volume of the present invention can also be determined by dispersing the no-binder filter medium in water in such a way that fibers are not destroyed.
- In the case of the no-binder filter medium also, if the wet sheet papermaking condition is not appropriate during sheet making, fibers cannot be distributed uniformly in the web, failing to achieve the above-mentioned PF value. Nonetheless, even a non-uniform sheet can be expected to raise the standard for the PF value by adopting the glass fiber raw material having the sedimentation volume of the present invention.
- The organic binder of the present invention is not limited to a particular type. However, widely used are synthetic resins such as acrylic resin, urethane resin, epoxy resin, olefin resin, polyvinyl alcohol resin, etc. Generally, these binder resins in the form of aqueous solution or aqueous emulsion are added to a filter medium by impregnation through immersion, or coating. Moreover, in order to reduce the surface tension of the binder liquid, an acetylene-based or fluorochemical surfactant may also be added thereto. Furthermore, in order to make the filter medium water-repellent, water-repellent agents may be added. Generally, these water-repellent agents, as well as binder resins, are added to the filter medium by immersion or spraying.
- Furthermore, in order to remove moisture from the sheet made from the filter medium or from the sheet provided with an organic binder liquid, the sheet is dried preferably at 110 - 150°C by using a hot air dryer or roll dryer.
- Acidic water of pH 2.5 with sulfuric acid was added to 90% by mass of borosilicate short glass fibers having an average fiber diameter of 0.65µm (106-475 manufactured by Johns-Manville Corporation) and 10% by mass of borosilicate short glass fibers having an average fiber diameter of 2.70µm (110X-475 manufactured by Johns-Manville Corporation) to give a concentration of 0.5% by mass. These raw materials were deflaked for a minute by using a food mixer (Product No. MX-V200 manufactured by Matsushita Electric Industrial; henceforth may be abbreviated simply as the "mixer") while the voltage supplied to the mixer (henceforth abbreviated as the "mixer voltage") was converted from the rated 100V to 70V (actual amperage of 2.9A) via a transformer. The deflaked dispersion was dispersed uniformly. Then, the deflaked raw materials were diluted to a concentration of 0.1% by mass in the same acidic water and made into a wet sheet of paper by using a handmade sheet molder, followed by drying at 130°C by using a roll dryer to obtain a filter medium having a basis weight of 70g/m2.
- As to Example 1, except that the mixer voltage of Example 1 was converted to 60V (actual amperage of 2.9A), the raw materials were deflaked for a minute in the same manner as in Example 1. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m2 was obtained in the same manner as in Example 1.
- As to Example 1, except that the mixer voltage of Example 1 was converted to 50V (actual amperage of 2.8A), the raw materials were deflaked for a minute in the same manner as in Example 1. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m2 was obtained in the same manner as in Example 1.
- Acidic water of pH 2.5 with sulfuric acid was added to 90% by mass of low boron short glass fibers having an average fiber diameter of 0.65µm (A06F manufactured by Lauscha Fiber International) and 10% by mass of low boron short glass fibers having an average fiber diameter of 2.70µm (A26F manufactured by Lauscha Fiber International) to give a concentration of 0.5% by mass. These raw materials were deflaked for a minute in a mixer while the voltage supplied to the mixer was converted from the rated 100V to 60V (actual amperage of 3.0A). The deflaked dispersion was dispersed uniformly. Then, the deflaked raw materials were diluted to a concentration of 0.1% by mass in the same acidic water and made into a wet sheet of paper by using a handmade sheet molder, which was dried at 130°C by using a roll dryer to obtain a filter medium having a basis weight of 70g/m2.
- As to Example 4, except that the mixer voltage was converted to 50V (actual amperage of 2.9A), the raw materials were deflaked for a minute in the same manner as in Example 4. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m2 was obtained in the same manner as in Example 4.
- As to Example 1, except that a standard disintegrator was adopted in place of the mixer, and the raw materials were deflaked by a standard disintegrator (JIS P 8220 enacted in 1998) at a rated voltage of 100V for a minute, the same process as Example 1 was used. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m2 was obtained in the same manner as in Example 1.
- As to Example 4, except that a standard disintegrator was adopted in place of the mixer, and the raw materials were deflaked by a standard disintegrator at a rated voltage of 100V for 30 seconds, the same process as Example 4 was used. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m2 was obtained in the same manner as in Example 1.
- Borosilicate short glass fibers made by a manufacturer which is different from that of Example 1 was used. Acidic water of pH 2.5 with sulfuric acid was added to 90% by mass of ultra fine glass fibers having an average fiber diameter of 0.65µm (B06F manufactured by Lauscha Fiber International) and 10% by mass of ultra fine glass fibers having an average fiber diameter of 2.70µm (B26R manufactured by Lauscha Fiber International) to give a concentration of 0.5% by mass. These raw materials were deflaked for a minute in a mixer while the mixer voltage was converted from the rated 100V to 80V (actual amperage of 2.9A). The deflaked dispersion was dispersed uniformly. Then, the deflaked raw materials were diluted to a concentration of 0.1% by mass in the same acidic water and made into a wet sheet of paper by using a handmade sheet molder, which was dried at 130°C by using a roll dryer to obtain a filter medium having a basis weight of 70g/m2.
- As to Example 8, except that the mixer voltage of 80 V was converted to 70V (actual amperage of 2.9A), the raw materials were deflaked for a minute in the same manner as in Example 8. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m2 was obtained in the same manner as in Example 8.
- In Example 4, acrylic latex (Trade Name: VONCOAT AN-155. Manufacturer: Dainippon Ink and Chemicals, Inc.) and a fluorochemical repellent agent (Trade Name: LIGHT-GUARD T-10. Manufacturer: Kyoeisha Chemical Co., Ltd.) were mixed to make a slurry of binder having a solid component ratio by mass of 100/5. The resulting wet sheet of paper was impregnated therein and dried at 130°C by using a roll dryer. A filter medium having a basis weight of 70g/m2 and an attached binder amount (solid content) of 5.5% by mass was obtained.
- As to Example 1, except that the rated voltage of 100V (actual amperage of 2.9A) was adopted for the mixer voltage, the raw materials were deflaked for a minute in the same manner as in Example 1. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m2 was obtained in the same manner as in Example 1.
- As to Example 1, except that the mixer voltage of Example 1 was converted to 80V (actual amperage of 2.9A), the raw materials were deflaked for a minute in the same manner as in Example 1. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m2 was obtained in the same manner as in Example 1.
- As to Example 1, except that the mixer voltage was converted to 40V (actual amperage of 2.6A), the raw materials were deflaked for a minute in the same manner as in Example 1. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m2 was obtained in the same manner as in Example 1.
- As to Example 4, except that the rated voltage of 100V (actual amperage of 3.0A) was adopted for the mixer voltage, the raw materials were deflaked for a minute in the same manner as in Example 4. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m2 was obtained in the same manner as in Example 1.
- As to Example 4, except that the mixer voltage was converted to 70V (actual amperage of 3.0 A), the raw materials were deflaked for a minute in the same manner as in Example 4. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m2 was obtained in the same manner as in Example 4.
- As to Example 4, except that the mixer voltage was converted to 40V (actual amperage of 2.6A), the raw materials were deflaked for a minute in the same manner as in Example 4. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m2 was obtained in the same manner as in Example 4.
- As to Example 1, except that a standard disintegrator was adopted in place of the mixer, and the raw materials were deflaked by using a standard disintegrator at a rated voltage of 100V for two minutes, the same process as Example 1 was used. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m2 was obtained in the same manner as in Example 1.
- As to Example 4, except that a standard disintegrator was adopted in place of the mixer, and the raw materials were deflaked by using a standard disintegrator at a rated voltage of 100V for a minute, the same process as Example 4 was used. The deflaked dispersion was dispersed uniformly. Then, a filter medium having a basis weight of 70g/m2 was obtained in the same manner as in Example 1.
- Acrylic latex (Trade Name: VONCOAT AN-155. Manufacturer: Dainippon Ink and Chemicals, Inc.) and a fluorochemical repellent agent (Trade Name: LIGHT-GUARD T-10. Manufacturer: Kyoeisha Chemical Co., Ltd.) were mixed to make a binder liquid having a solid component ratio by mass to be 100/5. The resulting liquid was sprayed onto the wet sheet obtained in Comparative Example 5, and then dried at 130°C by using a roll dryer. A filter medium having a basis weight of 70g/m2 and an attached binder amount (solid content) of 5.5% by mass was obtained.
- The following experiments were carried out for the filter media obtained in the Examples and Comparative Examples.
- Utilizing a self-made system, the pressure drop was determined by the use of a micropressure gauge while blowing air to a filter medium having an effective area of 100cm2 at an area wind speed of 5.3cm/sec.
- The upstream to downstream count ratio, namely DOP penetration, was determined by using a laser particle counter manufactured by Lion Corporation: Air containing poly-disperse DOP (dioctyl phthalate) particles generated by a Raskin nozzle was blown through a filter medium having an effective area of a 100cm2 at an area wind speed of 5.3cm/sec.
- Note that the target particles had a diameter in the range of 0.1 - 0.15µm. The DOP efficiency (%) was obtained by using the equation: 100 - (DOP penetration).
- The PF value which is the filter performance index of a filter medium was obtained by using the following Mathematical Formula 1: The higher the PF value, the higher the efficiency or the lower the pressure drop is.
[Math 2]
*The pressure drop in the mathematical formula 1 is determined when air passes the filter medium at a face velocity of 5.3cm/s (Unit: Pa). - Test strips cut out to a size of 1 inch width x 130mm length from a binder-attached filter medium was collected. They were spun stretched by a length of 100mm at a stretching speed of 15 mm/min by using a constant speed strograph (Strograph M1 manufactured by Toyo Seiki Co., Ltd.).
- This was obtained by the method described in Paragraph 0013.
- The dispersion performance of the constituting fibers was evaluated as follows: 50mL of the dispersed raw material slurry was collected and diluted 20 times in a 1 L graduated cylinder in water while shaking, which was subjected to visual inspection. The uniform dispersion condition free from sticking fibers or entangled fibers is considered to be an excellent dispersion performance. "O" represents excellent dispersion performance, and "X" represents poor dispersion performance.
- The binder component was removed from the binder-attached filter medium which was kept and sintered in an electric furnace at 500°C for 30 minutes. The pressure drop, DOP efficiency, PG value of the filter medium after binder was removed were determined by the previously described experiments (1), (2), and (3). Moreover, the sedimentation volume of the filter medium after binder was removed was determined in such a way that some area of the removal treated-filter medium was placed in pure water at room temperature (23°C) for 3 hours to be dispersed in the ultrasonic vibration treatment to obtain a slurry having a concentration of 0.04% by mass . Measurements were taken for the slurry by the method described in Paragraph 0013.
- The measurement results for the above experiments are shown in Tables 1∼5.
- Table 1 shows the results for the filter medium produced under the condition in which the mixer voltage was reduced and the number of rotation of the mixer blades was decreased. Between the rated voltage 100V and 80V, the sedimentation volume is low and the PF value level is also low. This is an indication that fibers were broken and shortened due to the high rotation number mixer processing. Under the condition of 70V - 50V, the sedimentation volume reaches over 450cm3/g and the PF value over 9.9, which indicates that a reduction of rotation number reduced the occurrence of fiber breakage, thereby significantly improving filter properties. However, in the 40V condition, the number of rotation is too small, deteriorating fiber dispersion performance and decreasing the PF value, although the sedimentation volume is high.
- Table 2 shows an example of low boron short fibers. In the same manner as in the case of borosilicate short glass fibers, a reduction in the number of rotations of the mixer blades provides the sedimentation volume of 450cm3/g or greater, which improves the PF value to 9 or more. The fact that the deterioration of fiber properties causes the PF value to diminish in the 40V condition is also the same. However, low boron short glass fibers are much more brittle than borosilicate short glass fibers, narrowing the range of suitable number of rotations. Even after an improvement is made, the PF value level is lower than that of borosilicate short glass fibers due to the properties of fibers themselves.
- Table 3 shows an example in which a standard disintegrator is used in place of a food mixer. The standard disintegrator, as compared to a mixer, provides different blade shapes and stirring conditions. Nonetheless, the PF value can be improved by using an appropriate disaggregation time to establish the sedimentation volume of 450cm3/g or greater. Furthermore, the excessively long disaggregation time indicates the advancement of fiber breakage.
- Table 4 shows the example in which the same borosilicate glass short fibers of a different manufacturer were used. In Examples 8 and 9, even though the same disaggregation condition as that of Comparative Example 2 was used, the sedimentation volume reached 450cm3/g or greater and the PF value 9.9 or greater. The average fiber length of the short glass fibers used in Examples 8 and 9 is surmised to be longer than that of the fibers used in Example 1 and Comparative Example 2.
- Table 5 shows the example of a binder-attached filter medium which was deflaked under the same condition as Examples 4 and Comparative Example 5 in which low boron short glass fibers were used. In any example, the attached binder increases the pressure drop with decreasing the PF value, while maintaining the same rate of decrease. In other words, the filter properties of the no-binder filter medium, which is the base, is reflected to the properties on the binder-attached filter medium. This is supported by the fact that, after the binder is removed, the property values of the no-binder filter medium, namely the sedimentation volume, pressure drop, efficiency, and PF value, are nearly reproduced.
[Table 1] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Short glass fibers Borosilicate short glass fibers Borosilicate short glass fibers Borosilicate short glass fibers Borosilicate short glass fibers Borosilicate short glass fibers Borosilicate short glass fibers Binder None None None None None None Water-repellent None None None None None None Attached Rinder Amount (solid content) % by mass 0 0 0 0 0 0 Disintegration method Food mixer Food mixer Food mixer Food mixer Food mixer Food mixer Disintegration condition Mixer voltage: 70V Mixer voltage: 60V Mixer voltage: 50V Mixer voltage: Rated 100V Mixer voltage: 80V Mixer voltage: 40V Disintegration time 1 minute 1 minute 1 minute 1 minute 1 minute 1 minute Dispersion evaluation O O O O O X Sedimentation volume cm3/g 450 650 875 275 325 950 Pressure drop Pa 441 435 436 446 441 437 0.1∼0.15µm DOP efficiency % 99.9965 99.9971 99.9967 99.9947 99.9940 99.9892 PF value 9.9 10.2 10.1 9.4 9.4 8.9 [Table 2] Example 1 Example 4 Example 5 Comparative Example 4 Comparative Example 5 Comparative Example 6 Short glass fibers Borosilicate short glass fibers Low boron short glass fibers Low boron short glass fibers Low boron short glass fibers Low boron short glass fibers Low boron short glass fibers Binder None None None None None None Water-repellent None None None None None None Attached Binder Amount (solid content) % by mass 0 0 0 0 0 0 Disintegration method Food mixer Food mixer Food mixer Food mixer Food mixer Food mixer Disintegration condition Mixer voltage: 70V Mixer voltage: 60V Mixer voltage: 50V Mixer voltage: Rated 100V Mixer voltage: 70V Mixer voltage: 40V Disintegration time 1 minute 1 minute 1 minute 1 minute 1 minute 1 minute Dispersion evaluation O O O O O X Sedimentation volume cm3/g 450 475 700 150 375 825 Pressure drop Pa 441 445 438 442 436 447 0.1∼0.15µm-DOP efficiency % 99.9965 99.9927 99.9932 99.9849 99.9853 99.9755 PF value 9.9 9.1 9.3 8.5 8.6 7.9 [Table 3] Example 1 Example 6 Example 4 Example 7 Comparative Example 7 Comparative Example 8 Short glass fibers Borosilicate short glass fibers Borosilicate short glass fibers Low boron short glass fibers Low boron short glass fibers Borosilicate short glass fibers Low boron short glass fibers Binder None None None None None None Water-repellent None None None None None None Attached Binder Amount (solid content) % by mass 0 0 0 0 0 0 Disintegration method Food mixer Standard disaggregation machine Food mixer Standard disaggregation machine Standard disaggregation machine Standard disaggregation machine Disintegration condition Mixer voltage: 70V Voltage: Rated 100V Mixer voltage: 60V Voltage: Rated 100V Voltage: Rated 100V Voltage: Rated 100V Disintegration time 1 minute 1 minute 1 minute 30 seconds 2 minutes 1 minute Dispersion evaluation O O O O O O Sedimentation volume cm3/g 450 700 475 575 250 150 Pressure drop Pa 441 442 445 440 437 445 0.1∼0.15µm DOP efficiency % 99.9965 99.9977 99.9927 99.9935 99.9930 99.9871 PF value 9.9 10.2 9.1 9.3 9.3 8.6 [Table 4] Example 1 Example 8 Example 9 Comparative Example 2 Short glass fibers Borosilicate short glass fibers Borosilicate short glass fibers Borosilicate short glass fibers Borosilicate short glass fibers Binder None None None None Water-repellent None None None None Attached Binder Amount (solid content) % by mass 0 0 0 0 Disintegration method Food mixer Food mixer Food mixer Food mixer Disintegration condition Mixer voltage: 70V Mixer voltage: 80V Mixer voltage: 70V Mixer voltage: 80V Disintegration time 1 minute 1 minute 1 minute 1 minute Dispersion evaluation O O O O Sedimentation volume cm3/g 450 650 925 325 Pressure drop Pa 441 435 436 441 0.1∼0.15µm DOP efficiency % 99.9965 99.9969 99.9970 99.9940 PF value 9.9 10.1 10.2 9.4 [Table 5] Example 4 Example 10 Comparative Example 5 Comparative Example 9 Short glass fibers Low boron short glass fibers Low boron short glass fibers Low boron short glass fibers Low boron short glass fibers Binder None Present None Present Water-repellent None Present None Present Attached Binder Amount (solid content) % by mass 0 5.5 0 5.5 Disintegration method Food mixer Food mixer Food mixer Food mixer Disintegration condition Mixer voltage: 60V Mixer voltage: 60V Mixer voltage: 70V Mixer voltage,: 70V Disintegration time 1 minute 1 minute 1 minute 1 minute Dispersion evaluation O O O O Sedimentation volume cm3/g 475 475 375 350 Pressure drop Pa 445 470 436 464 0.1∼0.15µm DOP collection efficiency % 99.9927 99.9946 99.9853 99.9894 PF value 9.1 8.9 8.6 8.4 Tensile strength (kN/m) kN/m - 0.94 - 0.68 Sedimentation volume after binder is removed cm3/g - 450 - 375 Pressure drop after binder is removed Pa - 443 - 437 0.1∼0.1 µm DOP efficiency after binder is removed % - 99.9921 - 99.9852 PF value after binder is removed - 9.1 - 8.6
Claims (3)
- An air filter medium comprising glass short fibers as its main fibers, characterized in that the main fibers are the fibers that constitute 70% or greater by mass of the total blended raw material fibers, the glass short fibers are low boron short glass fibers having a fiber diameter of less than 5 µm and length to diameter ratio of approximately 500:1 to approximately 3,000:1, the constituent fibers of the air filter are dispersed uniformly and, when said constituent fibers at a diluted concentration of 0.04% by mass are allowed to stand for 12 hours, the sedimentation volume is 450cm3/g or greater.
- An air filter medium according to claim 1 wherein said air filter medium as described in claim 1 in the no-binder condition has the PF value of 9.9 or greater when the PF value is expressed by the following equation (1):
[Math 1]
where the efficiency targets the particle diameter in the rage of 0.1 - 0.15µm and the face velocity is 5.3cm/sec. - An air filter medium according to claim 1 wherein said short glass fibers as described in claim 1 are low boron short glass fibers, and said air filter medium in the no-binder condition has the PF value of 9.0 or greater, when the PF value is expressed by the following equation (1),
[Math 2]
where the efficiency targets the particle diameter in the rage of 0.1- 0.15µm and the face velocity is 5.3cm/sec.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP14181614.0A EP2848295B1 (en) | 2008-03-25 | 2009-03-23 | Filter material for air filters |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2008078350 | 2008-03-25 | ||
PCT/JP2009/001259 WO2009119054A1 (en) | 2008-03-25 | 2009-03-23 | Filter material for air filters |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP14181614.0A Division EP2848295B1 (en) | 2008-03-25 | 2009-03-23 | Filter material for air filters |
Publications (3)
Publication Number | Publication Date |
---|---|
EP2275186A1 EP2275186A1 (en) | 2011-01-19 |
EP2275186A4 EP2275186A4 (en) | 2011-11-30 |
EP2275186B1 true EP2275186B1 (en) | 2014-09-10 |
Family
ID=41113265
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP09724703.5A Active EP2275186B1 (en) | 2008-03-25 | 2009-03-23 | Filter material for air filters |
EP14181614.0A Active EP2848295B1 (en) | 2008-03-25 | 2009-03-23 | Filter material for air filters |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP14181614.0A Active EP2848295B1 (en) | 2008-03-25 | 2009-03-23 | Filter material for air filters |
Country Status (6)
Country | Link |
---|---|
US (1) | US20090320428A1 (en) |
EP (2) | EP2275186B1 (en) |
JP (1) | JP5579055B2 (en) |
KR (2) | KR20160116012A (en) |
CN (1) | CN101896244B (en) |
WO (1) | WO2009119054A1 (en) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5536537B2 (en) * | 2010-05-21 | 2014-07-02 | 北越紀州製紙株式会社 | Air filter media |
JP6444878B2 (en) * | 2012-11-02 | 2018-12-26 | ユニフラックス ワン リミテッド ライアビリティ カンパニー | Treatment of tough inorganic fibers and their use in mounting mats for exhaust gas treatment equipment. |
WO2014171165A1 (en) * | 2013-04-15 | 2014-10-23 | 北越紀州製紙株式会社 | Filter material for air filter, method for manufacturing same, and air filter provided with same |
JP6087207B2 (en) * | 2013-05-13 | 2017-03-01 | 北越紀州製紙株式会社 | Filter material for air filter and method for producing the same |
WO2017022052A1 (en) | 2015-08-03 | 2017-02-09 | 北越紀州製紙株式会社 | Method for manufacturing filter medium for air filter |
CN105239461A (en) * | 2015-09-14 | 2016-01-13 | 中材科技股份有限公司 | High uniformity glass fiber liquid filtration material and preparation method thereof |
JP6673230B2 (en) * | 2017-01-12 | 2020-03-25 | ダイキン工業株式会社 | Air filter media |
KR20220034882A (en) * | 2019-07-19 | 2022-03-18 | 엔테그리스, 아이엔씨. | Porous Sintered Membrane and Method of Manufacturing Porous Sintered Membrane |
WO2022255453A1 (en) * | 2021-06-04 | 2022-12-08 | ダイキン工業株式会社 | Air filter medium, pleated filter medium, air filter unit, mask filtering medium, and method of recycling air filter medium |
Family Cites Families (26)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4239516A (en) * | 1979-03-08 | 1980-12-16 | Max Klein | Porous media to separate gases liquid droplets and/or solid particles from gases or vapors and coalesce entrained droplets |
JPS61266700A (en) | 1985-05-15 | 1986-11-26 | 山陽国策パルプ株式会社 | Production of glass paper |
JPS624418A (en) | 1985-06-29 | 1987-01-10 | Nippon Muki Kk | Glass fiber filter paper for air filter having ultrahigh performance |
JPS6221899A (en) | 1985-07-19 | 1987-01-30 | 山陽国策パルプ株式会社 | Production of glass paper |
JPS6221898A (en) * | 1985-07-19 | 1987-01-30 | 山陽国策パルプ株式会社 | Production of glass paper |
JP2764928B2 (en) | 1988-08-01 | 1998-06-11 | 日本板硝子株式会社 | Filter paper and method for producing the same |
JP2629327B2 (en) | 1988-12-26 | 1997-07-09 | 日本板硝子株式会社 | Filter paper and method for producing the same |
WO1996003194A1 (en) * | 1994-07-28 | 1996-02-08 | Pall Corporation | Fibrous web and process of preparing same |
JPH08229317A (en) * | 1995-03-02 | 1996-09-10 | Mitsubishi Paper Mills Ltd | Filter medium |
JPH1080612A (en) * | 1995-08-30 | 1998-03-31 | Mitsubishi Paper Mills Ltd | Filter material and air filter |
JP3761239B2 (en) * | 1996-02-16 | 2006-03-29 | 北越製紙株式会社 | Air filter medium and air filter |
JP3874038B2 (en) | 1996-11-29 | 2007-01-31 | 北越製紙株式会社 | Filter material for air filter and manufacturing method thereof |
US6358871B1 (en) * | 1999-03-23 | 2002-03-19 | Evanite Fiber Corporation | Low-boron glass fibers and glass compositions for making the same |
ATE538860T1 (en) * | 2000-08-21 | 2012-01-15 | Hokuetsu Kishu Paper Co Ltd | FILTER MEDIUM FOR AIR FILTRATION AND METHOD FOR PRODUCING THE SAME |
JP4891498B2 (en) * | 2001-09-06 | 2012-03-07 | 北越紀州製紙株式会社 | Filter material for air filter and method for producing the same |
JP3769242B2 (en) * | 2002-03-29 | 2006-04-19 | 日本板硝子株式会社 | Heat-resistant filter paper for air filter and method of using the same |
JP4108447B2 (en) * | 2002-11-06 | 2008-06-25 | 北越製紙株式会社 | Filter material for air filter and method for producing the same |
JP4184764B2 (en) | 2002-11-13 | 2008-11-19 | 北越製紙株式会社 | Air filter media |
JP2004352576A (en) * | 2003-05-30 | 2004-12-16 | Shinetsu Quartz Prod Co Ltd | Quartz glass fiber, quartz glass nonwoven fabric, and filter |
JP4511327B2 (en) * | 2004-11-17 | 2010-07-28 | 北越紀州製紙株式会社 | Filter material for air filter and method for producing the same |
JP4916888B2 (en) * | 2004-12-03 | 2012-04-18 | 三菱製紙株式会社 | Nonwoven fabric for gypsum board and method for producing the same |
JP4769508B2 (en) * | 2005-07-29 | 2011-09-07 | 北越紀州製紙株式会社 | Air filter media with low outgas |
JP5096726B2 (en) * | 2005-11-07 | 2012-12-12 | 三菱製紙株式会社 | Composite filter media |
JP5148888B2 (en) * | 2007-02-09 | 2013-02-20 | 北越紀州製紙株式会社 | Filter material for air filter and method for producing the same |
JP5052935B2 (en) * | 2007-03-29 | 2012-10-17 | 北越紀州製紙株式会社 | Filter medium for dust removal air filter and manufacturing method thereof |
JP4722965B2 (en) * | 2008-05-30 | 2011-07-13 | 日本無機株式会社 | Manufacturing method of air filter for high temperature |
-
2009
- 2009-03-23 EP EP09724703.5A patent/EP2275186B1/en active Active
- 2009-03-23 KR KR1020167026065A patent/KR20160116012A/en not_active Application Discontinuation
- 2009-03-23 WO PCT/JP2009/001259 patent/WO2009119054A1/en active Application Filing
- 2009-03-23 KR KR1020107011296A patent/KR101688015B1/en active IP Right Grant
- 2009-03-23 EP EP14181614.0A patent/EP2848295B1/en active Active
- 2009-03-23 CN CN2009801012766A patent/CN101896244B/en active Active
- 2009-03-23 JP JP2010505326A patent/JP5579055B2/en active Active
- 2009-08-12 US US12/462,997 patent/US20090320428A1/en not_active Abandoned
Also Published As
Publication number | Publication date |
---|---|
CN101896244A (en) | 2010-11-24 |
KR101688015B1 (en) | 2016-12-22 |
JPWO2009119054A1 (en) | 2011-07-21 |
EP2275186A4 (en) | 2011-11-30 |
EP2848295B1 (en) | 2017-04-26 |
KR20160116012A (en) | 2016-10-06 |
EP2275186A1 (en) | 2011-01-19 |
KR20110008153A (en) | 2011-01-26 |
US20090320428A1 (en) | 2009-12-31 |
CN101896244B (en) | 2013-08-28 |
WO2009119054A1 (en) | 2009-10-01 |
JP5579055B2 (en) | 2014-08-27 |
EP2848295A1 (en) | 2015-03-18 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP2275186B1 (en) | Filter material for air filters | |
EP2987544B1 (en) | Filter material for air filter, method for manufacturing same, and air filter provided with same | |
EP1242161B2 (en) | Low boron containing microfiberglass filtration media | |
US9012010B2 (en) | Nanofiber sheet and method for manufacturing the same | |
US20120160104A1 (en) | Filter media including glass fibers | |
JP7180713B2 (en) | Alumina fiber aggregate and manufacturing method thereof | |
US20100212272A1 (en) | Filter media suitable for ashrae applications | |
US20120152859A1 (en) | Filter media with fibrillated fibers | |
JP5148888B2 (en) | Filter material for air filter and method for producing the same | |
US8951324B2 (en) | Air filter medium | |
JP2017060932A (en) | Filter paper for filter and production method of the same | |
JP6270971B2 (en) | Filter material for air filter and method for producing the same | |
JP5536537B2 (en) | Air filter media | |
JP6964033B2 (en) | Filter material for air filter | |
JP2011062643A (en) | Filter medium for air filter | |
JP2014054595A (en) | Filter medium for air filter | |
JPH05261224A (en) | Filter material for air filter | |
JPH04284803A (en) | Glass fiber filter sheet for use in air filter of high performance | |
JP2003284908A (en) | Volume reduced high performance air filter medium reduced in stretchability and manufacturing method therefor |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 20100622 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK TR |
|
AX | Request for extension of the european patent |
Extension state: AL BA RS |
|
DAX | Request for extension of the european patent (deleted) | ||
A4 | Supplementary search report drawn up and despatched |
Effective date: 20111031 |
|
RIC1 | Information provided on ipc code assigned before grant |
Ipc: D21H 27/08 20060101ALI20111025BHEP Ipc: D21H 13/40 20060101ALI20111025BHEP Ipc: D04H 1/42 20060101ALI20111025BHEP Ipc: B01D 39/20 20060101AFI20111025BHEP |
|
RIC1 | Information provided on ipc code assigned before grant |
Ipc: D21H 27/08 20060101ALI20140227BHEP Ipc: D21H 13/40 20060101ALI20140227BHEP Ipc: B01D 39/20 20060101AFI20140227BHEP Ipc: D04H 1/42 20120101ALI20140227BHEP |
|
GRAP | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOSNIGR1 |
|
INTG | Intention to grant announced |
Effective date: 20140415 |
|
GRAJ | Information related to disapproval of communication of intention to grant by the applicant or resumption of examination proceedings by the epo deleted |
Free format text: ORIGINAL CODE: EPIDOSDIGR1 |
|
GRAP | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOSNIGR1 |
|
INTG | Intention to grant announced |
Effective date: 20140526 |
|
GRAS | Grant fee paid |
Free format text: ORIGINAL CODE: EPIDOSNIGR3 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK TR |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: FG4D |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: EP |
|
REG | Reference to a national code |
Ref country code: IE Ref legal event code: FG4D |
|
REG | Reference to a national code |
Ref country code: AT Ref legal event code: REF Ref document number: 686360 Country of ref document: AT Kind code of ref document: T Effective date: 20141015 |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R096 Ref document number: 602009026587 Country of ref document: DE Effective date: 20141023 |
|
REG | Reference to a national code |
Ref country code: SE Ref legal event code: TRGR |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: ES Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 Ref country code: FI Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 Ref country code: LT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 Ref country code: NO Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20141210 Ref country code: GR Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20141211 |
|
REG | Reference to a national code |
Ref country code: NL Ref legal event code: VDEP Effective date: 20140910 |
|
REG | Reference to a national code |
Ref country code: LT Ref legal event code: MG4D |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LV Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 Ref country code: CY Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 Ref country code: HR Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 |
|
REG | Reference to a national code |
Ref country code: AT Ref legal event code: MK05 Ref document number: 686360 Country of ref document: AT Kind code of ref document: T Effective date: 20140910 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: IS Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150110 Ref country code: CZ Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 Ref country code: EE Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 Ref country code: SK Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 Ref country code: RO Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 Ref country code: PT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150112 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: AT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 Ref country code: PL Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R097 Ref document number: 602009026587 Country of ref document: DE |
|
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DK Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 |
|
26N | No opposition filed |
Effective date: 20150611 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: IT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LU Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150323 Ref country code: MC Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: PL |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: SI Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 |
|
REG | Reference to a national code |
Ref country code: IE Ref legal event code: MM4A |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: CH Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20150331 Ref country code: LI Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20150331 Ref country code: IE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20150323 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: PLFP Year of fee payment: 8 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: BE Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: MT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: PLFP Year of fee payment: 9 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: BG Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 Ref country code: HU Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT; INVALID AB INITIO Effective date: 20090323 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: TR Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: PLFP Year of fee payment: 10 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: MK Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20140910 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20240321 Year of fee payment: 16 Ref country code: GB Payment date: 20240322 Year of fee payment: 16 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: SE Payment date: 20240321 Year of fee payment: 16 Ref country code: FR Payment date: 20240320 Year of fee payment: 16 |